Note 62 — Chapter IV · POLITICAL AND SOCIAL CONDITION OF IRELAND
Reading edition
This is clearly to be inferred from the Book of Rights, where no relations or mutual obligations are mentioned as existing between the three Ulster kings. Nor was there, since the destruction of the old Ulidian kingdom in the third century, any name to designate the whole province, for Ulaid was confined to the kingdom in the east of Ulster. The use of Ultonia to describe the province, as distinguished from Ulidia = Ulaid, is of course merely a literary convention.